Getting back into imaging after a long break

[Gina]

I have the rig temporarily attached to a length of wood which I've clamped to the observatory wall rather close to an apple tree but it'll do for testing.

[Gina]

First night sky image in Ha.  Exposure of 90s gain 240 temperature -21C (the best I'm getting at 100% cooling in the ASI 1800MM-Cool).  North is at around 5 o'clock.

Edited April 21, 2019 by Gina

[Gina]

Darker now and gain increased to 420 but it's showing noise.  I used to get -30C from this camera but not now. ?

[Gina]

What I don't understand is that I'm getting coloured noise from a monochrome camera with all mono processing AFAIK.

[Gina]

Here's an image converted from FITS to PNG format in PixInsight and contrast increased slightly.

[Gina]

3m exposure.  Converted from FITS to PNG in PI.  I think I may be seeing nebulae in the Milky Way in the bottom of the picture - NW.

[Gina]

If I can improve the cooling on the camera and increase the gain I think this technique may reveal the hydrogen gas clouds (nebulae).

I think it possible that directing the warm air from the camera up to the lens may be restricting it and reducing the amount of cooling available.  Maybe vent the air straight out and use some other way to stop dew on the lens.

Edited April 21, 2019 by Gina

[Gina]

Exposure increased to 4m.  Stars are now trailing.

[Gina]

OK 5 minutes exposure.

[Gina]

I'm going to try stacking.  This means that I've had to change the ROI to exclude ground based lights so that the stacking routine can use stars for alignment.  I have reduced exposure to 90s to avoid star trailing.  Maybe if I can get a dozen or two frames it might show the hydrogen clouds better.  I think the test so far shows promise.

Edited April 21, 2019 by Gina

[Gina]

Looks like I might have caught a meteor.  And clouds are coming in!  This is a screenshot from KStars FITS Viewer which seems to be trying to debayer a mono image!

[JamesF]

I believe we're pretty close to the Lyrid meteor shower, so perhaps not surprising that you've picked one up.  I've seen a few over a very short period of time tonight.  Still a nice thing to catch in an image though

James

[Xplode]

Focus seems pretty bad, maybe it would be easier to pick out the Ha if you get perfect focus?

[Gina]

Focus was adjusted remotely for sharpest image in daylight.

 

Edited April 22, 2019 by Gina

[Xplode]

The lens isn't very sharp then, i have a ASI178MC with a Fujinon lens and it has much sharper stars

[Gina]

Now running a test to see if the routing of air from the camera cooler up to the lens affects the cooling.  I ran the cooling for a while with the casing on with the unit indoors and then with the top of the casing removed so that the air was free to escape straight out.  There is a slight difference but it's only about 0.3°C - from -14.7°C to -15.0°C.  It is a warm day and the indoor temperature is around 22°C so the cooling may be struggling anyway.

EDIT - the camera temperature reading has now risen to -14.5°C so that small difference noted earlier is not significant - the ambient temperature is varying a lot more than that.

The cooling performance of this ASI 1600MM-Cool camera has definitely deteriorated then - I can get down to -20°C with the cooling system in my ASC with the DIY cooled ASI 178MC.  Maybe I would be better using the same system as in my ASC except with the mono version of the camera (ASI 178MM).

Edited April 22, 2019 by Gina

[Gina]

11 minutes ago, Xplode said:

The lens isn't very sharp then, i have a ASI178MC with a Fujinon lens and it has much sharper stars

This is the second Fujinon lens I've had and I think the first one was better.  OTOH I was using an ASI 185MC camera and the full colour spectrum in my ASC rather than Ha.

[Gina]

Taken the camera out of the bottom of the casing and sat it horizontally on the table and the temperature has decreased a couple more degrees so maybe the casing wasn't helping airflow into the camera.  The inlet was a lot bigger than the fan and shouldn't have affected the air flow.  However, I can easily give the camera an open mounting bracket.

I've also tried focussing and think I may have it a bit better.

Edited April 22, 2019 by Gina

[Gina]

Started thinking about this again following the successful night's imaging with my ASC and the Milky Way coming more and more into a favourable position in the sky.  I need to sort out better focussing I think and the mounting wants to allow clear airflow in and out of the ASI1600MM-Cool camera.  I may make up a dew heater for the lens rather than using the warm air for the camera cooling.  I bought a batch of 3W ceramic resistors for the ASC and have some left.

[JamesF]

Oooh, Gina!  I hadn't realised that you had an ASI1600.  Any chance you could plug it into a Linux box and try the latest release of oacapture?  I have reports of it crashing on MacOS, but it seems fine with the ZWO cameras that I have.  Knowing whether it works or not on Linux might be helpful and perhaps also easier to find out why if it doesn't.

No worries if it's too awkward to set up.  Just thought I'd ask as I'm a bit stuck for a way forward at the moment.

James

[Gina]

Can't see it being a problem.  I use Linux Mint on my desktop machine and Ubuntu MATE on RPi.  I think the desktop would be easiest and my desktop has USB3 whereas RPi is only USB2.  In fact I have two ASI1600s.  I also have ASI174MM, ASI178MM, ASI120MC-S and the ASC uses an ASI178MC.

Edited May 5, 2019 by Gina

[JamesF]

That would be very helpful.  Thank you.

James

[Gina]

Problem!

[JamesF]

Ah, you need to install the other packages first if you're doing it from a GUI because it won't know where to find them.  So, libasicamera, libefwfilter and libuvc (from the downloads page).

James

[Gina]

OK, I'll check that out tomorrow.